1. Field of the Invention
The present invention relates to the field of trailer wheels, and more particularly to a trailer wheel and method to seal the wheel bearings and associated components from water.
2. Description of the Prior Art
As is well known, boat trailers are frequently subjected to relatively difficult environmental use. Conventional hubcabs, while serving to protect the hub axle and bearing assemblies from contamination under certain conditions, are not always satisfactory for protecting the hub assemblies when they are immersed in water, as occurs as a result of normal use of the boat trailer. Due to the small diameter of the wheels of a boat trailer in relation to the diameter of the wheels of a towing vehicle, the hub axle and bearing assemblies of the wheels of the trailer frequently attain relatively high temperatures, especially when the trailer is towed for several hours over highways. When such conditions exist, they tend to liquefy the lubricant and, due to centrifugal force, air and lubricant escape from within the hubcab.
Frequently after a boat trailer has been towed many miles it is then backed into cold water to facilitate the removal and floating of the boat on the water. When this occurs, the entire hub assembly is suddenly cooled, contracting the air and lubricant within the cap and around the bearing assemblies. This creates a partial vacuum which causes water, sand and other contaminants to seep into the hub cap assembly in direct contact with the axle and bearings. When water enters the hubcab assemblies, it eventually causes rust and corrosion of parts of the wheel assembly and creates serious problems for safe, efficient and continued use of the trailer.
Various attempts have been made in order to overcome these problems associated with trailer wheels. In U.S. Pat. No. 3,785,706, issued to Vangalis on Jan. 15, 1974, there is disclosed a pressurized hub cap for a vehicle wheel. The Vangalis patent describes a cup-shaped cap having a flange which seats on the wheel hub. A helical spring urges a piston in the direction of the axle of the trailer to hold grease on the outside of the axle and associated nut. A vent hole is provided on the outside of the piston, and a second hole is provided to allow the escape of grease in the event that excessive expansion of the grease occurs. A similar construction is described in U.S. Pat. No. 4,106,816, issued to August on Aug. 15, 1978. In U.S. Pat. No. 3,955,852, issued to De Puydt et al. on May 11, 1976, there is also described a trailer hubcap device utilizing a spring-biased piston to pressurize grease against the outside of the axle and nut. The De Puydt et al. patent further describes a manual actuator to permit the pressure to be relieved while the trailer is being moved along a roadway.
A related hubcap construction is described in U.S. Pat. No. 3,649,080, issued to Molinare on Mar. 14, 1972. This patent describes a hubcab construction which includes a grease fitting to permit introduction of grease into the cap and also a pressure relief valve to provide for expansion of the grease. In U.S. Pat. No. 3,393,015, issued to Kaufman of July 16, 1968, there is described a hubcap which includes an O-ring normally positioned over a vent hole to prevent the entrance of water within the cap, but which will expand to uncover the hole for permitting air and grease to be vented from the hubcap when heated. A protective hubcap closure is described in U.S. Pat. No. 3,149,883, issued to Reilly on Sept. 22, 1964. The Reilly patent describes a hubcap which is flexible to become contracted or compressed when the trailer is immersed in cold water.
A different approach to the waterproofing for a hubcap is described in the Eberle patent, U.S. Pat. No. 3,226,162, issued on Dec. 28, 1965. The Eberle patent describes the use of a tube connecting from the pressurized tire to the hubcap, for permitting air to be vented into the hubcap as a method for pressurizing the cap to prevent entrance of water.